1 / 19

Lecture outline

Lecture outline. History/Introduction Microbiological Techniques/ Diversity Diversity/ Structure and function Prokaryotic structure and function Nuclear structure, cell walls etc…. Prokaryotic structure and function Prokaryotic structure and function Bacterial growth.

abedi
Download Presentation

Lecture outline

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture outline History/Introduction Microbiological Techniques/ Diversity Diversity/ Structure and function Prokaryotic structure and function Nuclear structure, cell walls etc…. Prokaryotic structure and function Prokaryotic structure and function Bacterial growth. Bacterial Genetic systems (LK)

  2. Cell-membrane Plasmid Flagellum Capsule Cell-wall Fimbrae Nucleus Simplified Bacterial Cell

  3. Cell Surface structures and Cell walls A. Flagellae B Pili and fimbrae C. Capsules D. Cell Walls, membranes and Peptidoglycan Membrane structure and function Gram Positive. Teichoic acids Gram negative. Outer membrane/ Lipopolysaccharide

  4. Cell Surface structures and Cell walls A. Bacterial flagellae Helical. Several times the length of the cell Single polar - E.coli as shown two polar - Pseudomonas spp. Very motile Axial filaments. Spirochetes. Subunits of flagellin protein. Helix arrangement. Self assembly. At least 12 genes control the basal components in E.coli.

  5. Cell Surface structures and Cell walls cont… Mechanism of motility Rotate rigidly, motor in cell membrane ATP not hydrolysed. Involves proton motive force in respiring membrane Multiple flagellae rotate in bundles Polystyrene beads Cell (Berg.H C. 1973)

  6. Bacterial flagellum structure and mechanism Flagellum rotates via “motor” in active membrane Gram Positive Gram Negative

  7. Cell Surface structures and Cell walls cont… Chemotaxis Motile bacteria swim toward attractants Positive and negative chemotaxis Sense environment. Surface receptors CHEMORECEPTORS over 20 recognised in E.coli Glucose Random motion

  8. Cell Surface structures and Cell walls cont… B. Pili and fimbrae. Filamentous appendages up to 30 m long and 20-30nm thick Self assembly Adhesion to surfaces Sex pili involved in conjugation C.Capsules and slime External layer of polysaccharide (except B antracisD-glutamic acid polymer) C/N nutrition dependent Homo or hetero polysaccharide (usually amino hexoses) Serves to protect cells egphagocytosis, dessication etc.

  9. D. Cell Walls, membranes and Peptidoglycan Membrane defines INSIDE and OUTSIDE Cell wall constructed OUTSIDE Wall is a RIGID structure. PEPTIDOGLYCAN Various polymers are interlinked to make ONE big polymer. Serves to protect the cells from harsh environments TEICHOIC ACIDS found only in GRAM positive cells either glycerol phosphate polymer or ribitol phosphate polymer

  10. Gram-negative Cell Wall Structure

  11. Gram-negative Cell Wall Structure

  12. Membrane structure and function Cytoplasmic or Plasma membrane Glycerophospholipids; fatty acid esters of glycerol 3-phosphate Arranged in fluid bilayer Many proteins arranged in membrane substrate transport functions respiration secretion and cell wall growth enzymes Glycerol 3-phosphate HYDROPHYLIC Long chain fatty acid HYDROPHOBIC

  13. Peptidoglycan Lipopolysaccharide Teichoic acids 1-2nm 20-80nm Peptidoglycan Cell membrane Cell membrane Gram Positive and Gram Negative Cell Types Outer-membrane GRAM POSITIVE GRAM NEGATIVE

  14. Gram-positive Cell Wall Structure

  15. Gram-positive Cell Wall Structure

  16. Gram-negative Cell Wall Structure

  17. [NAM-NAG] n L D L- NH2 D [D] Peptidoglycanstructure

  18. Peptidoglycan structure

  19. Lipopolysaccharidestructure

More Related